I've been training for my first IM, currently at week 17. I was naive in my original calculation of the zones and figured my run zone was 110-130. Having run longer Run races before, only recently did I started to question the validity of it given how slow I was going. I backed in to what a potential IM time would be and figured it couldn't be right.

This morning I proceeded to test the Run portion. I found my LTHR to be 185. Using the calculator in the settings suggested Z2 to be 158 - 168. That led to a mild freak out realizing for 17 weeks I've been basically walking for long periods of time. Also, knowing that that range seems really high to sustain.

After talking to a friend who's lose to the same age that has also completed a IM using the same plan, he suggested his Run Z2 was 138-148. That range seems much more doable to me. However, it's weird that my results were so off from the tests. I used the other formulas in the calculator on this site and one gave < 148, and the other 139-154. So that it around the same range my friend suggested.

So at this point, I'm wondering what is right? And what's the best way to really figure this out because at this point I'm both confused and totally freaked out!

After reading several links around the site, I have a feeling I did the LTHR TT wrong. How hard should the pace be? I was able to keep a VERY agressive pace going during the 30 min. but definitely nothing I could have sustained. The last sentence says "You should finish knowing you gave it everything you had", which is what led me to go "all out".

You should run at a near-steady pace that becomes progressively more difficult to maintain, esentially finishing at the point where you cannot maintain it any longer. Your avg. HR for the last 20min is a reasonable APPROXIMATION of your LTHR.

If running at the HRs 'prescribed' by the zones using that LTHR do not appear to correlate with your RPE, then there is a good chance that the data was bad (HR can vary for a number of reasons, maybe the monitor was not working well and you got some bad data points, etc.). Be willing to adjust to RPE and monitor your HR for the time being. Then, attempt to retest in a few weeks and see what comes up.

Edit: Also, if you have done running races, you can figure out your zones using paces as well. That's another tool you can use to guage effort or act as a check combined with HR.

Originally posted by JohnnyKay
Edit: Also, if you have done running races, you can figure out your zones using paces as well. That's another tool you can use to guage effort or act as a check combined with HR.

I did a Half marathon with a goal of 2 hr. The long slow runs on the weekend where at 10:30 pace. The race pace was slightly less than 9 min. So would that "race" pace be what I use for the LT time trial?

Originally posted by frist44 Hi, I've been training for my first IM, currently at week 17. I was naive in my original calculation of the zones and figured my run zone was 110-130. Having run longer Run races before, only recently did I started to question the validity of it given how slow I was going. I backed in to what a potential IM time would be and figured it couldn't be right. Thus, I found the following article: http://www.beginnertriathlete.com/cms/article-detail.asp?articleid=... This morning I proceeded to test the Run portion. I found my LTHR to be 185. Using the calculator in the settings suggested Z2 to be 158 - 168. That led to a mild freak out realizing for 17 weeks I've been basically walking for long periods of time. Also, knowing that that range seems really high to sustain. After talking to a friend who's lose to the same age that has also completed a IM using the same plan, he suggested his Run Z2 was 138-148. That range seems much more doable to me. However, it's weird that my results were so off from the tests. I used the other formulas in the calculator on this site and one gave < 148, and the other 139-154. So that it around the same range my friend suggested. So at this point, I'm wondering what is right? And what's the best way to really figure this out because at this point I'm both confused and totally freaked out! Thanks!

Heart rate zones are highly individual. For example, mine run high and my Z2 for running is slightly higher than the one that you calculated.

Originally posted by JohnnyKay
Edit: Also, if you have done running races, you can figure out your zones using paces as well. That's another tool you can use to guage effort or act as a check combined with HR.

I did a Half marathon with a goal of 2 hr. The long slow runs on the weekend where at 10:30 pace. The race pace was slightly less than 9 min. So would that "race" pace be what I use for the LT time trial?

No. Use the race result in a pace calculator like McMillan's (http://www.mcmillanrunning.com/). That will give you estimated paces for different types of running. Pace is an alternative to using HR but, similar to needing a decent estimate of your LTHR to find your HR zones, you need a decent race to get good estimates for your pace zones. By "decent", I mean one where you ran similar to a good HR test run (finished 'spent' at the end but didn't fade too much towards the later stages of the race).

For now, I'd use your half marathon run to get some estimated paces. Then play around in training and see if you can't "triangulate" pace, HR and RPE that seems to "fit" together and give you better estimates for your zones. Regardless, don't freak out about it. If you are running "too easy", the worst that will happen is that you won't get quite the training stimulus that you could. But if you run "too hard", there's a good chance you could end up injured. That leads to missed training and even less overall stimulus than if you had just kept it "too easy".

I haven't tried a workout in my calculated zone yet because it seemed so high. After more research on this site and others, it seems that somewhere around 150 is the high of Z2 for me. All ballparks...today I did the biking a in the new zone and it obviously felt more rigorous compared to what's I've been doing, but I was able to maintain just fine for 1 hr. and felt like I plenty left, so I guess it'll just take more experimentation.

Since all the calculations are all over the place, how do I come to an accurate conclusion about the upper bound of Z2? My worry is that I haphazardly decide on an upper bound, which ends up being too high and I don't get the same benefit in my training. Physically, would it just feel too high?

I haven't tried a workout in my calculated zone yet because it seemed so high. After more research on this site and others, it seems that somewhere around 150 is the high of Z2 for me. All ballparks...today I did the biking a in the new zone and it obviously felt more rigorous compared to what's I've been doing, but I was able to maintain just fine for 1 hr. and felt like I plenty left, so I guess it'll just take more experimentation.

Since all the calculations are all over the place, how do I come to an accurate conclusion about the upper bound of Z2? My worry is that I haphazardly decide on an upper bound, which ends up being too high and I don't get the same benefit in my training. Physically, would it just feel too high?

"Researching" your Z2, is probably not a very useful thing. People can have very different HR zones. The research will show where the averages lie and that might be a good random guess. But it's probably not a good idea to use blindly for training. It could be either much too low or much too high just as easily as it could be completely accurate.

Your HR zones will NOT be the same in different sports. You cannot use your run HRs for the bike (on AVERAGE, you'll see most people about 10bps lower on the bike for the same zones). You should establish those in testing on the bike.

The field test you did is probably the best way to go about figuring out your zones. But just because it is the "best" does not mean you will always get perfect results. It's a good starting point, but if it seems really off (not because it "sounds" too high relative to your research, but because it "feels" wrong when you try to actually run in those zones) then adjust and look to re-test.

There is no magic benefit to training in particular zones. What will happen is that if you train too hard in workouts that should be 'easy', you will have difficulty in those workouts that should be 'hard'. That's what will lead to sub-optimal training. It can also lead to injury if you constantly push too hard. If you run too easy in your 'easy' workouts, you just won't get as much benefit as you could and it will take you longer to make progress. That sounds like a huge problem, but it's really not that big a deal. Using HR is just a way to help you learn what "easy" and "hard" really feel like. People can (and do) train very successfully without ever knowing their HR. Don't let yourself get caught in the weeds and miss the big picture of WHY you are doing it.

All that said, I suggest you go out and try a short run in the Z2 range suggested by your test. See how it feels. If it really seems too hard (difficult to talk, etc.), then back off. Forget about HR for a couple weeks and just run at whatever feels easy ("conversational" pace). Then, do the test again and see what results you get. If it feels a bit challenging, but "OK", then try it on a longer run. Again, even if you stick with the zone for a bit, do another test in a few weeks.

Great advice, thanks! Went out today and was around 147-154 that felt easy going and something I could sustain for the long haul. To cross-check with my knowledge of running races, I took my phone and watch the timing pace, and found that indeed around 10min/mile was in the range where I felt comfortable. Today's run had some Z4 spurts in it, which went to mid 170's and around 7min/mile pace.

As you mentioned, going out and just doing what feels right probably makes more sense for me. I'm sure a pattern will emerge over the next few weeks that I will follow.

Thanks again for your help. It's good to hear that the first 15 weeks haven't been a total waste.

HR zones ARE very individual, so comparing yourself to a friend who is 'the same' as you doesn't really give you any better information than using the formulas. If you REALLY want to know, you need to have one of those threshold tests done where you get on a bike or treadmill and strap a mask to your face. I had it done and found out that the standard calculations were pretty far off for me, for example my zone 2 starts at 114 but goes to 141. The test cost me somewhere between $50-$80 (can't remember it was several years ago) and I had it done at Lifetime Fitness. (I wasn't a member, so it may be cheaper for members.)

I had the test done separately for the bike and the run, but the numbers were almost identical.

I highly recommend this, it removes that nagging question that is always in the back of your mind. Plus you will get your v02 max and you can plug that in to your HRM for more accurate calorie burn info, and you will see that you are extremely fit compared to the average Americans in your AG. (I am a steady back-of the pack triathlete and was in the 97%tile for my AG